[PATCH weston v2] data-device: Implement DnD progress notification

[Carlos Garnacho]

Weston now sends wl_data_source.drop_performed and .drag_finished in
order to notify about the different phases of DnD.

wl_data_source.cancelled is also used as mentioned in the docs, being
emitted also on DnD when the operation is meant to fail (eg. source
and dest didn't agree on a mimetype).

The dnd demo is also fixed so the struct dnd_drag isn't leaked.

https://bugs.freedesktop.org/show_bug.cgi?id=91943
https://bugs.freedesktop.org/show_bug.cgi?id=91944

Changes since v1:
  - Updated to protocol v2.

Signed-off-by: Carlos Garnacho <carlosg at gnome.org>
---
 clients/dnd.c     | 39 +++++++++++++++++++++++++++++++--------
 clients/window.c  |  2 +-
 src/compositor.h  |  2 ++
 src/data-device.c | 37 +++++++++++++++++++++++++++++++------
 4 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/clients/dnd.c b/clients/dnd.c
index e6a0c39..6c2ed57 100644
--- a/clients/dnd.c
+++ b/clients/dnd.c
@@ -318,14 +318,8 @@ data_source_send(void *data, struct wl_data_source *source,
 }
 
 static void
-data_source_cancelled(void *data, struct wl_data_source *source)
+destroy_dnd_drag(struct dnd_drag *dnd_drag)
 {
-	struct dnd_drag *dnd_drag = data;
-
-	/* The 'cancelled' event means that the source is no longer in
-	 * use by the drag (or current selection).  We need to clean
-	 * up the drag object created and the local state. */
-
 	wl_data_source_destroy(dnd_drag->data_source);
 
 	/* Destroy the item that has been dragged out */
@@ -339,10 +333,39 @@ data_source_cancelled(void *data, struct wl_data_source *source)
 	free(dnd_drag);
 }
 
+static void
+data_source_cancelled(void *data, struct wl_data_source *source)
+{
+	struct dnd_drag *dnd_drag = data;
+
+	/* The 'cancelled' event means that the source is no longer in
+	 * use by the drag (or current selection).  We need to clean
+	 * up the drag object created and the local state. */
+        destroy_dnd_drag(dnd_drag);
+}
+
+static void
+data_source_drop_performed(void *data, struct wl_data_source *source)
+{
+}
+
+static void
+data_source_drag_finished(void *data, struct wl_data_source *source)
+{
+	struct dnd_drag *dnd_drag = data;
+
+        /* The operation is already finished, we can destroy all
+         * related data.
+         */
+	destroy_dnd_drag(dnd_drag);
+}
+
 static const struct wl_data_source_listener data_source_listener = {
 	data_source_target,
 	data_source_send,
-	data_source_cancelled
+	data_source_cancelled,
+	data_source_drop_performed,
+	data_source_drag_finished,
 };
 
 static cairo_surface_t *
diff --git a/clients/window.c b/clients/window.c
index 47628de..24aa517 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -5376,7 +5376,7 @@ registry_handle_global(void *data, struct wl_registry *registry, uint32_t id,
 		d->shm = wl_registry_bind(registry, id, &wl_shm_interface, 1);
 		wl_shm_add_listener(d->shm, &shm_listener, d);
 	} else if (strcmp(interface, "wl_data_device_manager") == 0) {
-		d->data_device_manager_version = MIN(version, 2);
+		d->data_device_manager_version = MIN(version, 3);
 		d->data_device_manager =
 			wl_registry_bind(registry, id,
 					 &wl_data_device_manager_interface,
diff --git a/src/compositor.h b/src/compositor.h
index 4443c72..18266ef 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -304,6 +304,8 @@ struct weston_data_source {
 	struct wl_resource *resource;
 	struct wl_signal destroy_signal;
 	struct wl_array mime_types;
+	struct weston_data_offer *offer;
+	int accepted;
 
 	void (*accept)(struct weston_data_source *source,
 		       uint32_t serial, const char *mime_type);
diff --git a/src/data-device.c b/src/data-device.c
index 1612091..4be392d 100644
--- a/src/data-device.c
+++ b/src/data-device.c
@@ -62,12 +62,18 @@ data_offer_accept(struct wl_client *client, struct wl_resource *resource,
 {
 	struct weston_data_offer *offer = wl_resource_get_user_data(resource);
 
+	/* Protect against untimely calls from older data offers */
+	if (!offer->source || offer != offer->source->offer)
+		return;
+
 	/* FIXME: Check that client is currently focused by the input
 	 * device that is currently dragging this data source.  Should
 	 * this be a wl_data_device request? */
 
-	if (offer->source)
+	if (offer->source) {
 		offer->source->accept(offer->source, serial, mime_type);
+		offer->source->accepted = mime_type != NULL;
+	}
 }
 
 static void
@@ -76,7 +82,7 @@ data_offer_receive(struct wl_client *client, struct wl_resource *resource,
 {
 	struct weston_data_offer *offer = wl_resource_get_user_data(resource);
 
-	if (offer->source)
+	if (offer->source && offer == offer->source->offer)
 		offer->source->send(offer->source, mime_type, fd);
 	else
 		close(fd);
@@ -99,8 +105,18 @@ destroy_data_offer(struct wl_resource *resource)
 {
 	struct weston_data_offer *offer = wl_resource_get_user_data(resource);
 
-	if (offer->source)
+	if (offer->source) {
+		if (offer->source->offer == offer) {
+			if (offer->source->accepted)
+				wl_data_source_send_dnd_finished(offer->source->resource);
+			else
+				wl_data_source_send_cancelled(offer->source->resource);
+
+			offer->source->offer = NULL;
+		}
+
 		wl_list_remove(&offer->source_destroy_listener.link);
+	}
 	free(offer);
 }
 
@@ -147,6 +163,9 @@ weston_data_source_send_offer(struct weston_data_source *source,
 	wl_array_for_each(p, &source->mime_types)
 		wl_data_offer_send_offer(offer->resource, *p);
 
+	source->offer = offer;
+	source->accepted = 0;
+
 	return offer->resource;
 }
 
@@ -301,6 +320,7 @@ weston_drag_set_focus(struct weston_drag *drag,
 	serial = wl_display_next_serial(display);
 
 	if (drag->data_source) {
+		drag->data_source->accepted = 0;
 		offer = weston_data_source_send_offer(drag->data_source,
 						      resource);
 		if (offer == NULL)
@@ -398,9 +418,12 @@ drag_grab_button(struct weston_pointer_grab *grab,
 	enum wl_pointer_button_state state = state_w;
 
 	if (drag->base.focus_resource &&
+	    drag->base.data_source &&
 	    pointer->grab_button == button &&
-	    state == WL_POINTER_BUTTON_STATE_RELEASED)
+	    state == WL_POINTER_BUTTON_STATE_RELEASED) {
 		wl_data_device_send_drop(drag->base.focus_resource);
+		wl_data_source_send_dnd_performed(drag->base.data_source->resource);
+	}
 
 	if (pointer->button_count == 0 &&
 	    state == WL_POINTER_BUTTON_STATE_RELEASED) {
@@ -878,11 +901,13 @@ create_data_source(struct wl_client *client,
 	source->accept = client_source_accept;
 	source->send = client_source_send;
 	source->cancel = client_source_cancel;
+	source->offer = NULL;
+	source->accepted = 0;
 
 	wl_array_init(&source->mime_types);
 
 	source->resource =
-		wl_resource_create(client, &wl_data_source_interface, 1, id);
+		wl_resource_create(client, &wl_data_source_interface, 3, id);
 	wl_resource_set_implementation(source->resource, &data_source_interface,
 				       source, destroy_data_source);
 }
@@ -958,7 +983,7 @@ WL_EXPORT int
 wl_data_device_manager_init(struct wl_display *display)
 {
 	if (wl_global_create(display,
-			     &wl_data_device_manager_interface, 2,
+			     &wl_data_device_manager_interface, 3,
 			     NULL, bind_manager) == NULL)
 		return -1;
 
-- 
2.5.0